If you're a builder, it's totally worth it, but I don't think it's worth it just for the career. You might even find a mod just for a military career that dates pre Strangerville. It's probably not broken either, I've never had an issue with custom careers.
In my opinion, Strangerville is a great world with plenty of wonderful residential lots but the commercial lots are too tiny, especially the library. I think the build mode objects are amazing. I could care less about CAS but they did a good job there with making them workable. I think the whole storymode was fun to play but I'd never do it again. It was surprising at first with all the twists and turns, but once you know, you know and it's a little eh. The bizarre plants everywhere do NOT go away once you defeat the thing. (trying not to say it incase you don't know bc the surprise was WONDERFUL) and I really hate those lil ugly purple things. I've also noticed that any sims that live in strangerville can appear in any world walking around like a zombie and that kinda irritates me. It even happens after I defeat the thing. I also really wish I could edit the lab in the crater. I hate how it's locked because I NEED to give that place a makeover. I think if I went back in time AND I wasn't a builder, I probably wouldn't purchase Strangerville. If not for build mode, it's very... eh.